InverseJacobiSC[v, m] gives the inverse Jacobi elliptic function sc -1 (v \[VerticalSeparator] m).
InverseJacobiSD[v, m] gives the inverse Jacobi elliptic function sd -1 (v \[VerticalSeparator] m).
InverseJacobiSN[v, m] gives the inverse Jacobi elliptic function sn -1 (v \[VerticalSeparator] m).
KelvinBei[z] gives the Kelvin function bei(z).KelvinBei[n, z] gives the Kelvin function bei_n (z).
KelvinBer[z] gives the Kelvin function ber(z).KelvinBer[n, z] gives the Kelvin function ber_n (z).
KelvinKei[z] gives the Kelvin function kei(z).KelvinKei[n, z] gives the Kelvin function kei_n (z).
KelvinKer[z] gives the Kelvin function ker(z).KelvinKer[n, z] gives the Kelvin function ker_n (z).
MathieuC[a, q, z] gives the even Mathieu function with characteristic value a and parameter q.
MathieuS[a, q, z] gives the odd Mathieu function with characteristic value a and parameter q.
Nand
(Built-in Mathematica Symbol) Nand[e_1, e_2, ...] is the logical NAND function. It evaluates its arguments in order, giving True immediately if any of them are False, and False if they are all True.